Reference Guide

Virtual Link Trunking (VLT) | 1519

Virtual Link Trunking (VLT)

Overview

Virtual Link Trunking (VLT) is supported on the and platforms.

Virtual link trunking (VLT) allows physical links between two chassis to appear as a

single virtual link to the network core or other switches such as Edge, Access or ToR.

VLT reduces the role of Spanning Tree protocols by allowing LAG terminations on

two separate distribution or core switches, and by supporting a loop free topology. (A

Spanning Tree protocol is still needed to prevent the initial loop that may occur prior

to VLT being established. After VLT is established, RTSP may be used to prevent

loops from forming with new links that are incorrectly connected and outside the

VLT domain.) VLT provides Layer 2 multipathing, creating redundancy through

increased bandwidth, enabling multiple parallel paths between nodes and

load-balancing traffic where alternative paths exist.

Prerequisites: Before you configure VLT, make sure that both VLT peer switches are

running the same FTOS version and are configured for RSTP as described in the

Virtual Link Trunking (VLT) chapter in the FTOS Configuration Guide.

Commands

• back-up

• back-up destination

• clear vlt statistics

• delay-restore

• lacp ungroup member-independent

• peer-link

• peer-link port-channel

• primary-priority

• show vlt

• show vlt backup-link

Caution: Dell Force10 recommends not enabling Stacking and VLT simultaneously.

If both are enabled at the same time, unexpected behavior will occur.